With the greatest respect to the players here at EN World, I'd like to put forward my view. I've played from the red box right through AD&D, 2e and up to 3.5 as I play now. With each step I have found the game becomes simpler yet stronger and, with the small bugs and problems each re-write introduces not withstanding, I feel a more rounded and more easily-used game.
Being one of the lucky (we Brits seem to have the ability to truly pick and choose our players), I DM for two different groups every week, and have played long-term and regularly with over 6 different groups in the past few years. These players (about 30 in all) range from newbies who've never role-played before, through people who've played some, to people I've played with for 15 years straight. The newbies and the old-timers I have no problems with. The newbies learn to play in my style, which is very free-form and loose. The old-timers have been playing that style for years. Those who have played a bit of D&D or AD&D take a little time to settle in, but they come to get used to the system and enjoy the games.
No, my problems have all come from those who learned 3.x with another DM then came to my game. Why? Because they treat the game differently. Perhaps it's the way the rules are written down. Perhaps it's the way the rules are treated and described. Perhaps it's the advent of CRPGs and CCGs that players seem to 'graduate' from before they start role-playing.
These players argue constantly. These players count skill points. These players read up and remember monster weaknesses. These players track XP on their character sheets to go hunting for more when they get close to levelling up. These players hassle the DM constantly to see if they can add skill points and feats. These players bring no personality for their characters to the table, just a min/maxed set of numbers.
The players I've dealt with have come different DMs, so it can't just be the DM. I can only suggest it must be the system, and the way it puts the game across to new players. They are taught that this is a strategic simulation of dice rolling and collecting stuff. They are taught that characters only survive if they have at least average wealth for their level and items that boost every conceivable stat and some others.
As a DM I regularly run many types of game. High fantasy, low fantasy, space opera, horror, dungeon crawl... All using d20 and D&D. I can generally fit what I write to the type of game my players want at the time, and they enjoy it. Some of this group of players adapt to the style of DM I am (and stop checking SP etc.), but many have great difficulty with it, and they leave my game after arguments which amount to "I don't care if you're the DM, the rules apply to you too." As a DM I cut my teeth on AD&D, and DM'd right through 2e, and this doesn't feel right to me.
So I suppose my point is this: 3e has a different feel to it. It teaches new players to play a vastly different style of game to the old systems. Whilst those of us who learned to play in the previous systems have no problems picking up the system and making it feel and run like D&D always has, those who are new to our rarified hobby are getting a completely different feel for the game, especially when played without the benefit of experienced players from the older systems. That feel seems much more towards the kill things / get stuff / grow tougher / not much else feel of CCGs and CRPGs than the story systems I grew up playing.